The overall goals of this proposal are to examine geographical variation in the association between cancer risk and potential environmental exposures, in particular arsenic exposure, and to then determine the homogeneity of the associations as the geographical scale changes. Uses of Geographic Information Systems (GIS) have made it more feasible to link multiple sources of descriptive attribute information for various geographic levels with health outcome data. The use of GIS allows the spatial relationships between the data elements to maintained and analyzed. Arsenic exposure may be a causal agent in the development of bladder, lung, kidney, and skin cancers. Furthermore, arsenic is known to vary across geographical locations. Several geographically delineated data sets exist in the State of Arizona that allow for epidemiological exploration of the relationship between arsenic exposure and cancer occurrence. Geocoded cancer incidence and mortality data are available from the Arizona Cancer Registry for bladder, kidney, and lung cancer. Skin cancer data are available from a completed population-based case control study. Arsenic concentrations are available from a multimedia, multipathway survey conducted in Arizona. The specific aims for this proposed research are 1) to evaluate spatial scales and determine relationships between the scale used by the Atlas of Cancer Mortality and scales potentially more useful within the state and 2) to evaluate the relationships between the various cancers and arsenic exposure for the various geographical scales. This proposal presents a cohesive research team that encompasses faculty and staff from various colleges within the University of Arizona and state health agencies and will utilize archival data collected by various state agencies and completed epidemiological studies of skin cancer and environmental exposures.